Research On Random Short Delay Compensation Method For Networked Control Systems

Networked Control Systems(NCSs)are distributed closed-loop feedback control system formed by the rapid development of communication technology,computer network and control theory in recent years.It has broad application prospects in the field of industrial.Using the network to form a closed-loop control system,and the problems of network delay,packet loss and timing disorder will inevitably occur under the competitive communication protocol.This paper focuses on the impact of network random short delay on the performance of networked control systems.The main work is as follows:1)Aiming at the uncertainty of network delay,the Ping delay test software is developed.By measurnng and analyzing the round-trip delay(RTT)in the actual network,the delay prediction model of RBF neural network is established to predict the network delay.The experimental results show that the proposed method has better prediction accuracy and provides a basis for delay compensation of networked control systems.2)Aiming at the model problem of networked control systems,the discrete mathematical model of networked control systems with short delay and long delay is established respectively.The effects of sampling period and network delay on system stability and dynamic performance are analyzed by simulation.Then,the stability of networked control system is analyzing by using hybrid system theory,and the optimal selection method of sampling period is given in combination with the range of sampling period.The correctness of the method is verified by simulation experiments.3)Aiming at the problem of delay compensation,this paper validates the random short delay compensation method based on state estimation by combining the delay prediction model and the optimal selection method of sampling period,a short-delay,The delay in the network is compensated under state feedback and output feedback respectively.The simulation results show that the dynamic performance of the system after delay compensation has been significantly improved.